Step stool



FIG. 1 is a perspective view of a step stool showing my new design;

FIG. 2 is a top plan view of the step stool of FIG. 1;

FIG. 3 is a bottom plan view of the step stool of FIG. 1;

FIG. 4 is a left side elevation view of the step stool of FIG. 1;

FIG. 5 is a right side elevation view of the step stool of FIG. 1;

FIG. 6 is a front elevation view of the step stool of FIG. 1; and,

FIG. 7 is a rear elevation view of the step stool of FIG. 1. 

The ornamental design for a “step stool,” as shown and described. 